Ibuprofen is 2-(4-isobutylphenyl)propionic acid and is a non-steroidal anti-inflammatory compound (NSAID), which exhibits high levels of anti-inflammatory, analgesic and antipyretic activities necessary for the effective treatment of rheumatoid arthritis and osteo-arthritis and other inflammatory conditions. Most dosage forms of ibuprofen are immediate release dosage forms that provide rapid onset of therapeutic action, then rapidly declining levels of active ingredient, necessitating repeated dosing. They do not maintain therapeutic levels from one treatment over an extended period of time. Repeat dosing is thus required at intervals of four to six hours. Formulations that claim extended release fail to have an initial burst of the drug and thus exhibit substantial delay between administration and the achievement of an effective therapeutic blood level. Therefore, a need exists for a solid dosage form, for example a compressed tablet, which provides an initial burst of released ibuprofen, leading to prompt onset of action, then thereafter provides a sustained release of sufficient ibuprofen to maintain beneficial blood levels of ibuprofen over an extended period of 8 or more hours.
It is known ibuprofen is not directly compressible, and attempts to directly manufacture ibuprofen results in tablets which stick to the faces of the tableting press, are too friable for storage or transport, or split into two or more segments when expelled from the tableting press. To circumvent those manufacturing problems, those skilled in the art carry out a preliminary step prior to tableting, in which ibuprofen is wet granulated with a microcrystalline cellulose additive to form a granular composition comprising ibuprofen and microcrystalline cellulose, which is then capable of blending with further excipients and/or is directly compressible for the manufacture of a suitable solid dosage form. Therefore, a need exists for a dry blend of ibuprofen which is suitable for manufacture of a satisfactory tableted dosage form, obviating the need for a pre-granulation step.